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Nanoscale Probing of Interaction in Atomically Thin Layered Materials
ACS Central Science ( IF 12.7 ) Pub Date : 2018-02-12 00:00:00 , DOI: 10.1021/acscentsci.7b00590
Hossein Rokni 1 , Wei Lu 1
Affiliation  

We combine conductive atomic force microscopy (CAFM) and molecular dynamics (MD) simulations to reveal the interaction of atomically thin layered materials (ATLMs) down to nanoscale lateral dimension. The setup also allows quantifying, for the first time, the effect of layer number and electric field on the dielectric constant of ATLMs with few-layer down to monolayer thickness. Our CAFM-assisted electrostatic technique shows that high-quality mono- and bilayer graphene is reliably produced at significant yields only by the shear type of bond breaking between layers, whereas the normal type of bond breaking exhibits a very stochastic process mainly due to the coexistence of local delamination and interlayer twist. Our dielectric constant measurements also reveal a very weak dependence on the layer number and the electric field (up to our experimental limit of 0.1 V/Å), which is in contrast with theoretical reports. Owing to unexpectedly large variations in the screening ability of pristine monolayer graphene under ambient conditions, we further demonstrate that the effective dielectric constant of monolayer graphene can be engineered to provide a broad spectrum of dielectric responses (3.5–17) through oxidation and thermal annealing, thus confirming its much higher chemical reactivity than bilayer and few layers.

中文翻译:


原子薄层材料相互作用的纳米级探测



我们结合传导原子力显微镜 (CAFM) 和分子动力学 (MD) 模拟来揭示原子薄层材料 (ATLM) 的相互作用,直至纳米级横向尺寸。该装置还首次能够量化层数和电场对从几层到单层厚度的 ATLM 介电常数的影响。我们的 CAFM 辅助静电技术表明,仅通过层间的剪切型键断裂就能以显着的产率可靠地生产出高质量的单层和双层石墨烯,而普通类型的键断裂则表现出非常随机的过程,主要是由于共存局部分层和层间扭曲。我们的介电常数测量还揭示了对层数和电场的非常弱的依赖性(高达 0.1 V/Å 的实验极限),这与理论报告相反。由于原始单层石墨烯在环境条件下的筛选能力存在出乎意料的巨大变化,我们进一步证明,单层石墨烯的有效介电常数可以通过氧化和热退火进行设计,以提供广泛的介电响应(3.5-17),从而证实其化学反应活性比双层和几层高得多。
更新日期:2018-02-12
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